Literally it means shit-indie
However as this means it is a term rather open to interpration a better definition would run thus:
A musical genre which is largely mainstream, as equally related to pop as it is to true indie, rather devoid of talent and/or personality and, cynics would argue, produced purely for a quick buck by a celebrity seeking band.
Shindie is of course followed by fans of shindie- "shindies" or "shindie kids" who wear all the stereotypical "indie clothes" and try far too hard to be indie, sort of similar to the wannabe or scene kid in the emo social group.
True followers of shindie will NEVER admit that the music they listen to is shindie.